You must install "swisscom / ai-research-keyphrase-extraction"
from: https://github.com/swisscom/ai-research-keyphrase-extraction

Follow the installation guide to install "ai-research-keyphrase-extraction" as well as "stanford-corenlp-full-2018-02-27".

After that, add the files in this directory to the "ai-research-keyphrase-extraction" directory.
